Look for your model or serial number go to www.hp.com type in your model and see what the type of HDD is uses or can handle. How old is it? Is it 3 years or less. You might be able to use 160GB or 80GB. Check on the HP site first.

That model uses an ATA or PATA drive, not a SATA drive.
It will easily work with drives up to 80 GB. Some drives from 100 to 160 GB give this system board a lot of trouble... and some are not recognized, nor will they boot. There are both 7200 rpm and 5400 rpm drives available. The 5400 drives will seem slightly slower, but they last twice as long.